Meaning of 馬齢重 in Japanese

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Definition of 馬齢重

おもい(omoi) 【重い】

(adj-i) heavy; weighty; massive
heavy (feeling); depressed; gloomy; blue; uneasy
「彼の病気は重いのかな」「そうでないといいね」
"Is he seriously ill?" "I hope not."
slow; sluggish; lumbering; ponderous; clumsy
important; serious; grave
serious; severe; critical
solid; established; dignified; sensible

ばれい(barei) 【馬齢】